Eating less may prevent the onset of diseases such as Alzheimer's and Parkinson's, according to research.

A study carried out at the University of Wisconsin-Madison, in the US, found that reducing intake of food can improve the quality of life in older age and reduce the effects of ageing on the brain.

Researchers suggest this could prevent the onset of diseases affecting the brain, such as Alzheimer's and Parkinson's.

They examined the genetic activity of two regions of the brain; the cerebral cortex, the part involved in the higher functions of thought, and the cerebellum, the part that co-ordinates motor and muscle function.

They charted changes in the genetic activity in two groups of ageing mice, one group on a standard diet and the other whose diets have been cut to 76% of the standard diet.

It was found that a reduced-calorie diet cut the activity of genes linked to stress responses in the body that cause inflammation and the release of free radicals.

Free radicals are highly reactive molecules that circulate in the body and can damage cells over time.

Previous studies have suggested that both inflammation and free-radical damage may play a role in the onset of Alzheimer's and Parkinson's disease.

Health benefits

According to Richard Weindruch, one of those involved in the study, their findings show that a reduced-calorie diet can result in "health benefits" that can greatly improve the quality of life in old age.

"Although it is known that caloric restriction retards certain aspects of ageing in the brain, the mechanism is not known," he said.

"However, these new findings advance our understanding of caloric restriction's effects on ageing in the brain."

Another member of the research team, Tomas Prolla said the study's findings could help to devise new drug treatments for some diseases.

"It means we can use mice to screen for drugs that might prevent these processes in humans."

The study also suggests that the basic ageing mechanism in the human brain are shared among different species of animals, including mice, monkeys and humans.